Find the value of the path integral $f. dl clockwise around the closed path formed by the lines x = 0, x=a, y = 0 and y=b, where f = xyê + (3x² - y)û .

Currents in dc transmission lines can be 100 a or higher. some people are concerned that the electromagnetic fields from such lines near their homes could pose health dangers. for a line that has current 150 a and a height of 8.0 m above the ground, what magnetic field does the line produce at ground level? express your answer in teslas and as a percentage of the earth’s magnetic field, which is 0.50 g. is this value cause for worry?